Elastic-bodied crawler plate and crawler band

ABSTRACT

The present invention is an elastic-bodied crawler plate and crawler band which have a service life substantially equal to that of an integral rubber crawler band and are convenient to replace at the time when damaged or the like. To this end, an elastic-bodied crawler plate (10) integrally formed by embedding a core body (2) in an elastic body (1), is constructed so that a side surface in a longitudinal direction of a link is defined by an inversely-warped initial contact surface (1d) which extends from a link mounting surface side to a ground contacting surface side, and a subsequent contact surface (1e), which connects an end of the ground contacting surface side of the inversely-warped initial contact surface (1d) and an end of a ground surface (11). Further, an endless crawler band (100) is connected so as to provide a specified space (e) between rectangular parallelepiped elastic bodies (1A) of adjacent elastic-bodied crawler plates (10a, 10b).

TECHNICAL FIELD

The present invention relates to an elastic-bodied crawler plate and anendless crawler band, and particularly to an elastic-bodied crawlerplate and an endless crawler band for crawler vehicles of constructionequipment, agricultural machinery, etc.

BACKGROUND ART

Conventionally, in a crawler vehicle, such as a bulldozer or the like, atrack frame is provided between an idler wheel and a drive sprocket,with a plurality of upper rolling wheels and lower rolling wheels beingprovided on upper and lower parts of this track frame and with a steelcrawler band winding around each of these rolling wheels; and thevehicle is moved by driving the drive sprocket. In this ordinary steelcrawler band, a steel crawler plate 42 is clamped to a pair of right andleft links 41a and 41b by bolts 43, with links 41a and 44a, which arelongitudinally adjacent to each other, being connected together by thepin 45, and with links 41b and 44b, which are longitudinally adjacent toeach other, being connected together by a pin 45; and this ordinarysteel crawler band is integrally and endlessly formed, as illustrated inFIGS. 12A and 12B. In the drawings, 46 is a nut.

However, a steel crawler band with the above-described construction hasa disadvantage of directly contacting and damaging the surface of a roadwhen a vehicle equipped with the steel crawler band travels on thepavement, etc., to a site for operation; therefore, the surface of theroad requires protection by laying down a mat or the like thereon forprotecting the road surface. Accordingly, a long time is required fortraveling which causes a reduction in operational efficiency. Inaddition, great vibration and noise are generated while traveling, andespecially for construction in urban areas, it is necessary to reducethese vibrations and noise.

As a crawler band eliminating these above-described disadvantages, anintegrally formed rubber crawler band is adopted in which metal coremembers are embedded at specified intervals in an endless rubber band,and the band is driven by engaging these metal core members with a drivesprocket so that a long practical service life is obtained. However,there are disadvantages whereby even a crack or the like generating atonly one point can easily result in cutting the rubber crawler band, sothat the use of the rubber crawler band itself cannot be continued,since the rubber crawler band is integrally formed.

Next, as another crawler band eliminating disadvantages of a steelcrawler band such as damage on a road surface, etc., there are thefollowing crawler bands and crawler plates.

a) A crawler band is known in which a crawler plate is made by coveringa metal core member with rubber in the form of a block, and this rubbercrawler plate is directly clamped to a link by a bolt (refer to, forexample, Japanese Utility Model Application Laid-open No. 4-56593).

However, in this rubber crawler plate, in which rubber is bonded to ametal core member having a convex-concave surface, elastic distortion ofthe rubber is blocked by this convex-concave surface and distortion isconcentrated, so that fatigue cracks are easily generated in thevicinity of the convex-concave surface; thus, this rubber crawler platehas an inadequate service life. Other crawler plates, in which metalcore members are covered, are disclosed in Japanese Utility ModelApplication Laid-open No. 3-47290 and in Japanese Patent ApplicationLaid-open No.5-286463.

However, since these are crawler plates in which metal core members andlinks are integrally formed, at the time of the replacement of a rubbercrawler plate as a result of damage, etc., it is necessary to replaceand assemble a rubber plate integrally formed by attaching and detachingthe link pins to replace only one plate; and it becomes a burdensomeoperation requiring a number of man hours, so that they have thedisadvantage of being inconvenient to replace. Further, the replacementof the links is also included, so that they also have a disadvantageeconomically.

b) It is known that rubber or the like can be bonded with a metal platehaving a convex-concave part formed so as to hold the grouser on theground facing surface side of the steel crawler plate, and the metalplate and the links are clamped by a bolt with the steel crawler platebetween them (refer to, for example, Japanese Utility Model ApplicationLaid-open No. 5-78684). Similarly, it is known that rubber or the likecan be fastened to a steel plate formed so as to hold the grousertherein, then this steel plate and the steel crawler plate are clampedby a bolt, and this steel crawler plate and the links are furtherclamped by the bolt (refer to, for example, Japanese Utility ModelApplication Laid-open No. 6-10088).

However, in these crawler plates, the inside of the elastic bodies haveuneven elastic distortion because of the grouser of the steel crawlerplates, and fatigue cracks quickly generate at these points, so thatthese crawler plates have an inadequate service life.

c) It is known that rubber can be bonded only on the ground facingsurface side of a steel crawler plate by baking, and this rubber crawlerplate and the links are clamped (refer to, for example, Japanese PatentApplication Laid-open No. 5-305883).

However, such a crawler plate has a thinner portion in the thickness ofthe rubber, and a crack, fracture, or the like is easily generated, sothat such a crawler plate has an inadequate service life. The inventionwhich improves this foremost end portion is disclosed in JapaneseUtility Model Application Laid-open No. 4-84092. However, when therubber crawler band rides on a small stone or the like, the crawler bandinversely warps, with the rubber winding around the portions whichbecome inversely-warping stoppers at this time, that is, the foremostend portions in a longitudinal direction of the crawler plate, and withthe thickness of the rubber being inadequate, so that stress thereonbecomes high, a crack is easily generated. Further, the right and leftforemost end portions of the crawler plate are not covered with rubber,so that there is a disadvantage of easily generating a crack, fracture,etc.

BRIEF SUMMARY OF THE INVENTION

The present invention is made in order to eliminate the above-describeddisadvantages of the conventional art, and its object is to provide anelastic-bodied crawler plate and an endless crawler band which have aservice life for the crawler plate substantially equal to that of anintegral rubber crawler band and which provide convenience in replacinga crawler plate when the crawler plate is damaged.

The first aspect of the elastic-bodied crawler plate relating to thepresent invention is a crawler plate of an endless crawler band,constructed by clamping the crawler plate to a link by bolts and byconnecting a plurality of links with the crawler plate attached theretoby pins, and is characterized by the crawler plate including an elasticbody, provided with an inserting hole for the bolt, and a core body,provided with a bolt fitting hole. This core body is integrally formedby being embedded in the elastic body, and is characterized by the corebody having a bolt head bearing surface and an area in the vicinitythereof and a link mounting surface and an area in the vicinity thereofrespectively exposed, i.e., not covered with the elastic body. It ispreferable that, in a section in a longitudinal direction of the link ofthe elastic-bodied crawler plate, i) a ground facing surface has a flatsurface or a curved surface substantially parallel to the link mountingsurface, ii) a total width of the crawler plate in the longitudinaldirection of the link is smaller than a link pitch, iii) a width of theground facing surface in the longitudinal direction of the link issmaller than the total width of the crawler plate, iv) a side surface,in the longitudinal direction of the link, is formed by aninversely-warped initial contact surface extending from the linkmounting surface side toward the ground facing surface side, and asubsequent contact surface, connecting the end portion of thisinversely-warped initial contact surface closest to the ground facingsurface with the end portion of the ground facing surface, and v) anangle formed by a line, extending from a center of a link pin tangentialto the inversely-warped initial contact surface, with a line extendingfrom the center of the link pin perpendicular to the ground facingsurface, is equal to or less than an angle formed by a line connectingthe center of the link pin to the subsequent contact surface with theline extending from the center of the link pin perpendicular to theground facing surface.

On the ground facing surface side of the elastic-bodied crawler plate, asquare ground contacting surface can be formed in a central portion inthe longitudinal direction of the crawler plate, with a taperingtrapezoidal ground contacting surface formed on both ends of the squareground contacting surface in the longitudinal direction of the crawlerplate, and a steering surface in the form of a slanting trapezoid can beformed between the trapezoidal ground contacting surface and a side endportion in the longitudinal direction of the elastic-bodied crawlerplate. The above-described square ground contacting surface can be asquare ground contacting surface forming a concave portion to thetrapezoidal ground contacting surface. In addition, the ratio of aheight from the surface of the ground contacting surface to the corebody, to the link pitch can be in the range of 0.26 to 0.4. The ratio ofa distance from the side surface, in the longitudinal direction of thelink, of the ground contacting surface having the bolt inserting hole tothe inner surface of the bolt inserting hole to a hole diameter of thebolt inserting hole can be 0.75 or more. Further, the ratio of a concaveportion depth of the square ground contacting surface to the height fromthe ground contacting surface to the core body is larger than 0 and is0.49 or less. Furthermore, the ground facing surface of the core bodycan be a smooth surface.

According to the first aspect of the invention with the above-describedconstruction, by embedding the core body other than the link and thebolt attaching surfaces in the elastic body, the core body and theelastic body have a larger contacting area so that higher bonding forcecan be obtained, and the end portion of the bonding area, which easilyforms a starting point of a crack at the time of operation, ispositioned in a portion with smaller stress caused by deformation or thelike, so that the generation of cracks can be sharply reduced.

As for the surface, in the longitudinal direction of the link, of thecrawler plate (elastic crawler plate) which contacts an adjacent crawlerplate at the time of inverse warping of the crawler plate, theinversely-warped initial contact surfaces are in positions nearer to thelink mounting surfaces than to the ground contacting surfaces and beginto contact each other, unlike the conventional art in which the elasticbodies contact in the vicinity of the ground contacting surfaces. Morespecifically, in the conventional art, when riding on stones, etc., thedeformation caused by the elastic bodies contacting each other in thevicinity of the ground contacting surfaces is synergistic with thedeformation caused by riding on stones, etc., to cause the groundcontacting surfaces of the rubber crawler plates to locally deform so asto generate great stress, so that cracks, etc., are easily generated. Onthe other hand, in the present invention, the inversely-warped initialcontact surface is near the link mounting surface, so that the groundcontacting surface of the elastic body can be prevented from beinglocally deformed. As the inversely-warped angle increases, thecontacting area is expanding in the direction of both sides of theinversely-warped initial contact surfaces, that is, in the directions ofthe link mounting surface side and of the ground contacting surfaceside, and the repulsive elastic force of the adjacent elastic-bodiedcrawler plates to each other is increased, so that the load is dispersedto the adjacent crawler plate, and local deformation caused by theconcentrated load is not generated. Further, by the above-describedconstruction, even when riding over comparatively large stones, etc.,the inversely-warped elastic body rides thereon in such a way as tocover the stones, etc., so that uneven distortion is not generatedinside the elastic body and gradual elastic deformation can be obtained.

As for the ground contacting surface side of the crawler plate,trapezoidal ground contacting surfaces, with the width becoming smallertowards the end surfaces, are provided on both ends, in the longitudinaldirection of the crawler plate, of the square ground contacting surface,so that tortional deformation can be reduced even when the end portionof the crawler plate rides on earth, etc., at the time of operation, andgreater tractive force can be obtained. Slanting surfaces formed on bothsides, in the longitudinal direction of the link, of these trapezoidalground contacting surfaces prevent a sideslip of the crawler plate byholding earth and easily remove any stones caught therein. In addition,steering surfaces, in the form of a slanting trapezoid, are formed onboth right and left end portions on the ground surface side, so thatsteering resistance becomes smaller compared to the case in which theseslanting surfaces are not formed, and excellent operability can beobtained.

By forming a square ground contacting surface having a concave portion,and by providing specified ratios in a depth of the concave portion ofthe square ground contacting surface, a height from the trapezoidalground contacting surface to the core body, and a distance between theend portion of the ground contacting surface and the inner surface ofthe bolt inserting hole, the extent of the external damage on the groundcontacting surface side after a test of specified time can be reduced.Further, the core body has a smooth surface on its ground facing surfaceside, so that the elastic body is evenly deformed at the time ofoperation, unlike the case of the conventional metal core member havinga projecting portion; thus, the generation of cracks can be reduced.

The second aspect of the elastic-bodied crawler plate relating to thepresent invention is a crawler plate of an endless crawler bandconstructed by clamping the crawler plate to the links by bolts, andconnecting a plurality of links with the crawler plates attached theretoby pins, and is characterized by the crawler plate including an elasticbody in the form of a trapezoidal elastic body and a rectangularparallelepiped elastic body integrally formed on the bottom of thetrapezoidal elastic body; by the core body, with smooth surfaces on boththe top and bottom thereof, being integrally formed by being embedded inthe rectangular parallelepiped elastic body; by the elastic body beingprovided with bolt inserting holes, with the core body being providedwith bolt attaching holes having bolt head bearing surfaces and an areain the vicinity thereof, and a link mounting surface and an area in thevicinity thereof respectively being exposed; and by the trapezoidalelastic body gradually decreasing the trapezoidal sectional area fromthe region of the bolt inserting holes forming a central portion in thelongitudinal direction of the crawler plate to the ends on both sides,in the longitudinal direction of the crawler plate, to form slantingsurfaces of a trapezium on both side surfaces, in the longitudinaldirection of the link, of the trapezoidal elastic body.

By the above-described construction, as in the first aspect of theinvention, the elastic body is evenly deformed so that the generation ofcracks can be reduced, and any stones caught therein are easily removed,while a sideslip of the crawler plate is prevented.

The endless crawler band relating to the present invention ischaracterized by the elastic-bodied crawler plate of the above-describedsecond aspect of the invention being clamped to the links by bolts, witha plurality of clamped links being connected by pins, so that aspecified space is provided between the rectangular parallelepipedelastic bodies of the adjacent elastic-bodied crawler plates toconstruct an endless crawler, characterized by the above-describedspecified space being a space in which respective curved lines, in theform of a circular arc, pass through the boundary portions between therectangular parallelepiped elastic bodies and the trapezoidal elasticbodies on the opposing surfaces of the adjacent elastic-bodied crawlerplates, with the centers of the link pins on the other side of theadjacent elastic-bodied crawler plates as the centers thereof, have apoint of intersection between the opposing rectangular parallelepipedelastic bodies, and characterized by the boundary portions becominginversely-warped contact portions when the endless crawler isinversely-warped, so that the adjacent elastic-bodied crawler platescontact each other.

According to the above-described construction, as the inversely-warpedangle becomes larger, the elastic bodies are warped with the amount oflap increasing, and the elastic members of the adjacent crawler platesbecome contacting members, compressing each other and at the same timerepelling each other, so as to become stoppers in the inversely-warpeddirection of the link. Thereby, when inversely-warping is generated onthe ground facing side of the crawler band at the time of traveling, theadjacent crawler plates contact each other and elastic repulsive forceadditionally bears the vehicle weight, so that the durability of theelastic bodies is improved. In addition, when inverse warping isgenerated on the non-ground side of the crawler band at the time oftraveling, the elastic members forming the opposing surfaces of theadjacent crawler plates become the inversely-warping stopper, so thatthe crawler band can be prevented from twisting while traveling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an elastic-bodied crawler plate relating to thefirst embodiment of the present invention, seen from the ground surfaceside;

FIG. 2 is a front view of the elastic-bodied crawler plate in the firstembodiment;

FIG. 3 is a sectional view taken along line 3--3 in FIG. 1;

FIG. 4 is a condition in which the elastic-bodied crawler plate in thefirst embodiment is clamped to the links and is an explanatory view seenfrom a side surface;

FIGS. 5A and 5B are views illustrating the inverse warping of adjacentelastic-bodied crawler plates in the first embodiment, with FIG. 5Abeing an explanatory view of the beginning of the inverse warping, andFIG. 5B being an explanatory view when the inversely-warped angle islarge;

FIG. 6 is an explanatory view of the space between the adjacentelastic-bodied crawler plates in the first embodiment;

FIG. 7 is an explanatory view of a malfunction in the case when thespace, between the adjacent elastic-bodied crawler plates in FIG. 6, istoo large;

FIG. 8 is a graph showing the relationship between the wall thicknessratio, of the elastic-bodied crawler plate in the first embodiment, andthe degree of damage;

FIG. 9 is a front view of an elastic-bodied crawler plate relating tothe second embodiment of the present invention;

FIG. 10 is a graph showing the relationship between the ratio of thedepth, of the concave portion of the elastic-bodied crawler plate in thesecond embodiment, and the degree of damage;

FIG. 11 is a graph showing the relationship between the lug heightratio, of the elastic-bodied crawler plate in the second embodiment, andthe degree of damage; and

FIGS. 12A and 12B illustrate the construction of an ordinary steelcrawler band relating to the conventional art, with FIG. 12A being aplan view and FIG. 12B being a side view.

BEST MODE FOR CARRYING OUT THE INVENTION

A preferable embodiment of the elastic-bodied crawler plate and thecrawler band relating to the present invention will be particularlydescribed below with reference to the attached drawings.

In FIG. 1 to FIG. 3, an elastic-bodied crawler plate 10 of the firstembodiment is defined and is integrally formed by a core body 2 and anelastic body 1 having the core body 2 embedded therein so as to becovered therewith. This embedded core body 2, in the form of asubstantially rectangular plate, has a mounting surface 8 for a pair oflinks 4 and an area in the vicinity of the mounting surface 8, bolt headportion bearing surfaces 7 and their external perimeter, and bolt holes6, which are exposed, i.e., not covered with the elastic body 1. In FIG.2, showing the elastic-bodied crawler plate 10 in its longitudinaldirection, the length of the core body 2 is greater than a groundcontacting surface 11.

On the other hand, the ground facing surface side of the elastic body 1is provided at four positions with bolt inserting holes 5, each having ahole diameter D, and comprises: a square ground contacting surface 1a atthe central portion in the longitudinal direction of the elastic-bodiedcrawler plate 10, trapezoidal ground surfaces 1b at both right and leftsides of this square ground surface 1a (the boundary between the squareground surface 1a and each trapezoidal ground surface 1b on the drawingis illustrated by a two-dot chain line in FIG. 1), steering surfaces 1cat both ends, each in the form of a trapezoid slanting toward the linkmounting surface side, slanting surfaces 1f extending from the endportions of the trapezoidal ground surfaces 1b and the steering surfaces1c toward the link mounting surface side; subsequent contact surfaces1e, each forming a slanting surface extending toward the link mountingsurface side from a side portion of the square ground contacting surface1a; and inversely-warped initial contact surfaces 1d, each extendingfrom a subsequent contact surface 1e to the end portions of the linkmounting surface. This slanting surface 1f is a trapezium. The ratio ofa distance a (refer to FIG. 3), from the side portion of the groundsurface 11 of this subsequent contact surface 1e to the inner surface ofthe bolt inserting hole 5, to the hole diameter D of the bolt insertinghole 5 is 0.75 or more.

As FIG. 1 illustrates, the elastic-bodied crawler plate 10 is secured toa pair of links 4 by means of bolts which are not illustrated in thedrawings, and a plurality of links 4, having this elastic-bodied crawlerplate 10 attached thereto, are pivotally connected by means of pins 3 soas to define a crawler band.

FIG. 4 illustrates an explanatory view of an end surface of thiselastic-bodied crawler plate 10 in a condition in which the crawlerplate is secured to the links 4. The ground contacting surface 11 is aflat surface or a curved surface which is substantially parallel to themounting surface of the link 4, and a total width L2 of theelastic-bodied crawler plate is smaller than a link pitch L1, while awidth L3 of the ground contacting surface 11 is smaller than the totalwidth L2 of the elastic-bodied crawler plate 10. This total width L2 ismade to be smaller than the link pitch L1; however, when the pressure onthe ground contacting surface 11 is high, it is preferable in most casesto make the value of the total width L2 to be close to the value of thelink pitch L1 to reduce the pressure on the ground contacting surface 11and to increase the mass of the elastic body 1.

An angle θ1, which is formed by a line extending from a center P0 of alink pin so as to be tangential to the inversely-warped initial contactsurface 1d, and a line extending from the center P0 of the link pin soas to be perpendicular to the ground contacting surface 11, is equal toor less than an angle θ2 formed by a line connecting the center P0 ofthe link pin to an arbitrary point P2 on the subsequent contact surface1e, and the line extending from the center P0 of the link pinperpendicular to the ground contacting surface 11. FIG. 4 shows that theinversely-warped initial contact surface 1d is a flat surfacesubstantially parallel to the above-described line which isperpendicular to the ground contacting surface 11, and that thesubsequent contact surface 1e is a surface slanting from a contact pointP1 (an initial contact portion, which is also the end portion of theinversely-warped contact surface 1d closest to the ground contactingsurface 11), to the ground contacting surface end portion P2; however,the inversely-warped initial contact surface 1d is also a surface havinga portion with which the adjacent elastic body 1 starts to contact wheninverse warp occurs, so that the inversely-warped initial contactsurface 1d can be a curved surface, a concave surface, a convex surface,etc.

Accordingly, it is obvious that the tangential line forming the angle θ1is not limited to the line connecting the center P0 of the link pin andthe lower end portion of the inversely-warped initial contact surface1d; for example, when the inversely-warped initial contact surface 1d isa convex surface, the contact point P1 forming the inversely-warpedinitial contact portion can be in the middle portion of the convexlycurved surface. The subsequent contact surface 1e is a surface withwhich the adjacent elastic body 1 contacts after the contact point P1 ofthe inversely-warped initial contact surface 1d contacts the adjacentelastic body 1, and can be a curved surface, a concave surface, a convexsurface, a compound surface created by two or more surfaces, etc.

Further, the side surface extending from the link mounting surface tothe end portion of the ground contacting surface 11, that is, theinversely-warped initial contact surface 1d and the subsequent contactsurface 1e, can be a curved surface such as a convex surface, etc., acontinuously curved surface, a compound surface connecting a number offlat planes, etc., and can be a surface having the contact point P1 at aposition closer to the link mounting surface 8 than the groundcontacting surface 11.

Further, as for the position of the contact point P1 of theinversely-warped initial contact surface 1d in the direction of theheight of the elastic body 1, the contact point P1 can be at anyposition closer to the link mounting surface 8 than the groundcontacting surface 11; however, considering the prevention of localdeformation in the vicinity of the ground contacting surface 11, a valueof the ratio L5/L4≦0.8 is preferable. Here, L4 is the distance betweenthe link mounting surface and the ground contacting surface 11 of theelastic body 1, and L5 is the distance between the link mounting surface8 and the contact point P1 of the elastic body 1. Considering gentledeformation, etc., of the entire body of the adjacent elastic body 1, itis further preferable that the ratio L5/L4 be in the region of 0.6 orless.

In this construction, first of all, the core body 2, except for theportions whereto the links 4 and the bolts are attached, is embedded inthe elastic body 1, so that the area where the core body 2 and theelastic body 1 contact is large, and high bonding force can be obtained.In addition, the elastic body 1 is deformed by tractive force,rotational resistance force, etc., added thereto at the time ofoperation, and the edge of the portion where the core body 2 and theelastic body 1 bond together easily falls off, but the core body 2 iscovered with the elastic body 1, so that the frequency of the occurrenceof the edge portion falling off can be greatly reduced. Further, thelength of the core body 2, in the longitudinal direction of theelastic-bodied crawler plate 10, is greater than the length of theground contacting surface 11, so that the core body 2 supports a loadwhen conducting an operation laterally, or when running across bumps;therefore, the elastic-bodied crawler plate 10 is prevented from beingdamaged.

As for the sides of the ground contacting surface 11 of theelastic-bodied crawler plate 10, wherein the width of the trapezoidalground contacting surfaces 1b become smaller towards the end surfaces,even if an end portion of the elastic-bodied crawler plate 10 runs onthe earth, etc., tortional deformation is small and the elastic-bodiedcrawler plate 10 is excellently engaged into wet ground, etc., so thatgreater tractive force can be obtained. The slanting surface 1f preventsa sideslip of the crawler plate 10 by firmly holding the earth, andexcellently removes the stones caught therein. Further, with eachsteering surface 1c in the form of a slanting trapezoid, the steeringresistance becomes small compared to the case in which these slantingsurfaces are not formed, so that excellent operability can be obtained.

FIGS. 5A and 5B are schematic views of two inversely-warpingelastic-bodied crawler plates 10 adjacent to each other. As FIG. 5Aillustrates, inverse warping brings about an inversely-warped angle θ3.In the present embodiment, as described in the above (refer to FIG. 4),the total width L2 of each elastic-bodied crawler plate is smaller thanthe link pitch L1, and the angle θ1 at the contact point P1 on theinversely-warped initial contact surface 1d is equal to or less than theangle θ2 at the end portion P2 , which is an arbitrary point on thesubsequent contact surface 1e. As a result, at the start of inversewarping, the elastic-bodied crawler plates 10 adjacent to each othercontact each other at their contact points P1, and then with the angleslightly greater than the initial inversely-warped angle θ3, thevicinities around the contact points P1 contact each other, with theelastic body 1 being slightly deformed. When inverse warping furtheradvances and the angle becomes much greater than the initialinversely-warped angle θ3, most parts of the adjacent inversely-warpedinitial contact surfaces 1d contact each other, and the contactingportions of the subsequent contact surfaces 1e increase from the contactpoint P1 , so that deflection of each elastic body 1 is easily releasedto the ground facing surface side.

As the inversely-warped angle θ3 becomes even greater, the elastic body1 deflects entirely. Further, when the angle becomes greater so as to bethe inversely-warped angle θ4, the deflection generated on the entirebody of the elastic body 1 further increases, but local deformations arenot generated. For example, when running on a bump 12 with a largeextent of convexity, as illustrated in FIG. 5B, the ground contactingsurface 11 contacts the large area of the bump 12 so as to cover thebump 12 while almost the entireties of each of the inversely-warpedinitial contact surfaces 1d and each of the subsequent contact surfaces1e of the adjacent elastic bodies 1 contact each other, elasticallyrepelling each other to share the load. As described above, with a steepinversely-warped angle being obtained, the load can be prevented fromlocally concentrating. Further, even when earth, sand, etc., is caughtbetween the contacting surface portions, it is easily removed therefromwhen lifting, so that foreign substances are excellently removed.

FIG. 8 illustrates the relationship between the ratio of the distance ato the hole diameter D (refer to FIG. 3) and the degree of damage on theelastic-bodied crawler plate 10, and is a result of an endurance test byvehicles incorporating various levels of the distance a. Here, as forthe degree of the damage on the elastic-bodied crawler plate 10, thedegree of damage mainly in the vicinity of the bolt inserting holes 5 onthe ground facing side was assessed based on the presence or absence ofthe value as merchandise. A degree of damage of 0.3 at the end of theendurance test is the limit of the acceptable level. From the result ofthe endurance test, as the wall thickness ratio γ (=a/D) is increasing,the degree of damage decreases, and an elastic-bodied crawler plate witha wall thickness ratio γ of 0.75 or more is regarded as having value asmerchandise.

In the present embodiment, as FIG. 1 illustrates, the trapezoidal groundsurfaces 1b are formed between the rectangular ground contacting surface1a and the steering surfaces 1c; however, the length of the rectangularground contacting surface 1a in the longitudinal direction of theelastic-bodied crawler plate 10 can be extended and formed so as tocontact the steering surface 1c, and the ground contacting edges of thesteering surfaces 1c can be formed to be long so as to suit the lengthof the rectangular contact surface 1a to form the elastic-bodied crawlerplate. Explaining with reference to FIG. 6, each elastic-bodied crawlerplate can be defined by an elastic body in the form of a trapezoidalelastic body 1B (in the drawing, below the one-dot chain line) and arectangular parallelepiped elastic body 1A (in the drawing, above theone-dot chain line) integrally formed on top of the trapezoidal elasticbody 1B, and the core body 2 with smooth surfaces on the top and bottom,integrally formed by being embedded in the rectangular parallelepipedelastic body 1a.

The form of the core body 2, having a projection such as a convexportion or the like on the ground facing surface, as in the conventionalmetal core member, can be used as the core body 2 for the elastic-bodiedcrawler plate of the present invention; however, the ground facingsurface is preferably a smooth surface, as illustrated in FIG. 1 to FIG.3. With this smooth surface being provided, internal stress generated inthe elastic body 1 is evenly distributed, so that a starting point of acrack, which often generates in the vicinity of the core body 2, can beprevented from generating. Here, the smooth surface on the ground facingside means a form whereby distortion is not concentrated in the vicinityof the core body 2 of the elastic body 1; that is, a form which is notabruptly changed to be a concave form or a convex form or the like, anda surface having a mild concave surface or convex surface can besuitable besides a flat surface, a curved surface, a slanting surface inthe form of a concave surface or a convex surface, etc. Further, anordinary radius R, fillet, etc., can be applied to the end portion andthe corner of the core body 2, in order to prevent stress concentration.

The space between adjacent elastic-bodied crawler plates 10 will bedescribed with reference to FIG. 6. An endless crawler band 100, part ofwhich is illustrated in the drawing, is an endless crawler band in whichthe elastic-bodied crawler plate in FIG. 1 is fastened to links 4 (4a,4b) by bolts, and in which a plurality of links 4a and 4b are connectedby the pins 3 so as to be pivotable. Here, adjacent elastic-bodiedcrawler plates 10a and 10b are attached, with a specified space e beingprovided when the links 4a and 4b are in a straight line condition.

A preferable space e, described above, is determined as follows.Specifically, curved lines Ca and Cb, which have the link pin centersP0a and P0b as their centers with radiuses Ra and Rb, pass throughinversely-warped initial contact portions P1a and P1b of theelastic-bodied crawler plates 10a and 10b and intersect at a point ofintersection Co. Then, when the opposing upper end portions on the linkmounting side of the elastic-bodied crawler plates 10a and 10b arereferred to as P3a and P3b, the space e is set so that the point ofintersection Co is positioned at the point surrounded by theabove-described P1a, P3a, P3b, and P1b. When the point of intersectionCo is positioned between P1a and P1b, the inversely-warped initialcontact surfaces 1da and 1db contact each other from the beginning, andsuch a situation is not preferable.

By setting the above-described specified space e, when traveling onlevel ground without inversely-warping, the inversely-warped initialcontact surfaces 1da and 1db do not contact each other, so that repeatedelastic deformation is not generated on the same spot. Accordingly,fatigue failure of the elastic body 1 can be reduced. The upper limit ofthe position of the point of intersection Co is on the line made by P3aand P3b, since with the point of intersection Co at a position higherthan the above-described upper limit, the space between the adjacentinversely-warped initial contact surfaces 1da and 1db becomes too largeand the inversely-warped initial contact surfaces 1da and 1db cannotfunction properly as inversely-warping stoppers. More specifically, evenif an extremely large inversely-warped angle is given, theinversely-warped initial contact surfaces 1da and 1db do not contacteach other, so that an endless crawler band 101 with an extremely largeinversely-warpe angle has "waviness" generated while traveling, and amalfunction, such as the crawler band falling off, etc., easily occurs,as illustrated in FIG. 7.

A further preferable example of the space e is the case in which thespace e is set so that the curved lines Ca and Cb pass through theinversely-warped initial contact points P1a and P1b and the opposingupper end portions P3b and P3a on the link mounting side or thevicinities of the upper end portions P3b and P3a, as illustrated in FIG.6. In this case, when traveling with inverse warping generating, theinversely-warped initial contact portions P1a and P1b, forming thickwall portions of the elastic bodies 1, contact each other at thebeginning, and the contacting area increases as the inversely-warpedangle becomes larger. However, great elastic deformations are notgenerated in the portion with smaller wall thickness; more specifically,in the vicinities of the upper end portions P3a and P3b, and in theportions near the side of the core body 2 on the inversely-warpedinitial contact surfaces 1da and 1db, so that fatigue failure in theseportions with smaller wall thicknesses can be reduced.

From the above, by providing a specified space e, large elasticdeformation in the elastic body, especially in the portions with smallerwall thicknesses is prevented when traveling on level ground, or evenwhen traveling on an area generating inverse warping. It is consideredto be effective for increasing longevity that the core body 2 has asmooth surface. Further, the elastic-bodied crawler plate 10 is attachedand detached only by removing the bolts for attachment as with a steelcrawler plate, and can be attached and detached in a short time, so thatthe elastic-bodied crawler plate 10 is convenient to replace at the timeof damage, etc.

Next, the second embodiment of the elastic-bodied crawler plate and theendless crawler band related to the present invention will be describedwith reference to the attached drawings. The main point of theelastic-bodied crawler plate of the present embodiment which isdifferent from the first embodiment is a construction forming the squareground contacting surface 1a (refer to FIG. 1).

In FIG. 9, in an elastic body 15, a concave square ground facing surfaceportion 1al, forming a concave portion of the ground surface 11, isformed in the central portion of the ground surface 11 in thelongitudinal direction of an elastic-bodied crawler plate 20; and on theupper side of the core body 2, the elastic body 15 is provided withsubstantially uniform thickness extending up to the link mountingsurface 8. The other things are the same as in the elastic-bodiedcrawler plate 10 in the first embodiment. Here, when the height from theground contacting surface 11 to the ground facing side surface of thecore body 2 is H, the depth from the ground contacting surface 11 to theconcave square ground facing surface 1a1 is h, and the link pitch is L1(refer to FIG. 4), the concave portion depth ratio α (=h/H) is largerthan 0 and is 0.49 or less. The lug height ratio β (=H/L1) is in therange of 0.26 to 0.4.

The elastic-bodied crawler plate 20 in this construction is regarded ashaving value as merchandise when the concave portion depth ratio α is0.49 or less, as illustrated in FIG. 10. This is because cracks areeasily generated at the root of a lug when the depth of the concaveportion is too large. It should be mentioned that the degree of damageand the limit of the passing level are defined as being the same as inFIG. 8.

As FIG. 11 illustrates, the elastic-bodied crawler plate 20 is regardedas having value as merchandise when the lug height ratio β is 0.26 ormore. When the lug height ratio β is less than 0.26, the mass ofdeformation of the elastic body 1 is small, so that the degree of damageincreases. When the lug height ratio β is more than 0.4, a vehicle maybe rocked while operating on the side, and operability such as drivingcomfort or the like may be reduced, so that the lug height ratio β ispreferably in the range of 0.26 to 0.4. The relationship between the lugheight ratio β and the degree of damage (refer to FIG. 8) in the firstembodiment is also the same as described above. It should be mentionedthat as for the relationship between the wall thickness ratio γ (=a/D)and the degree of damage (refer to FIG. 8), the same result is obtainedwith the elastic-bodied crawler plate 20 in the present embodiment.

In the above, the elastic-bodied crawler plate related to the presentinvention is described, and as for the elastic body, relatively softmaterial such as rubber, polyurethane, resin, non-metal composites orthe like can be used, while as for the core body, material havingstrength such as the ordinary conventional metal core member materialsuch as steel, cast steel, cast iron or the like, material havingstrength such as metal composites, non-metal composites, or the like canbe used. This core body is embedded in the elastic body, and ordinarybonding, adhesion, or the like, such as vulcanizing adhesion ordinarilyconducted in the case of rubber, or the like, is applied thereto. As forthe bolts for attaching to the link, ordinary bolts can be used, but theuse of hexagon socket head bolts is preferable because the boltinserting holes can be made smaller, so that the distance a (refer toFIG. 3) between the bolt inserting hole and the end surface of thesquare ground facing surface becomes longer and the degree of damagebecomes smaller.

Industrial Applicability

The present invention is useful as an elastic-bodied crawler plate andan endless crawler band which have a service life substantially equal tothat of an integral rubber crawler band, with the generation of fatiguecracks, etc., of the elastic body being greatly reduced, and which areconvenient to replace at the time of damage or the like.

I claim:
 1. An elastic-bodied crawler plate having a longitudinallength, a transverse width, a link mounting surface side, a groundcontacting surface side, opposite longitudinally extending sides, andopposite longitudinal ends, said crawler plate comprising:an elasticbody including holes for inserting bolts therethrough; a core bodyhaving a smooth top surface, without an abrupt convex or concave form,and a smooth bottom surface, without an abrupt convex or concave form;said smooth top surface including a link mounting surface; said corebody having a plurality of bolt attaching holes formed therein so as toextend through said link mounting surface; said crawler plate beingintegrally formed by said core body being embedded in said elastic bodywith said core body having exposed surfaces which are not covered bysaid elastic body and with said link mounting surface side includingsaid link mounting surface; said exposed surfaces including bolt headbearing surfaces and said link mounting surface.
 2. A crawler plate inaccordance with claim 1, wherein said ground contacting surface sideincludes a ground contacting surface, and wherein a width of said groundcontacting surface gradually decreases from a central area of saidcrawler plate toward each longitudinal end of said crawler plate,without changing the width of said link mounting surface side of saidcrawler plate.
 3. A crawler plate in accordance with claim 1, whereinsaid elastic body comprises a rectangular parallelepiped elastic bodysection forming an elastic body portion of said link mounting surfaceside of said crawler plate and a trapezoidal elastic body sectionforming an elastic body portion of said ground contacting surface sideof said crawler plate.
 4. A crawler plate in accordance with claim 3,wherein said trapezoidal elastic body section has longitudinallyextending sides and opposite ends, wherein each longitudinally extendingside of said trapezoidal elastic body section comprises first and secondslanting surfaces with each extending from said central area of saidcrawler plate to a respective end of said trapezoidal elastic bodysection.
 5. A crawler plate in accordance with claim 4, wherein each endof said trapezoidal elastic body section is in the form of a trapezoidalend surface slanting in an inward direction from said rectangularparallelepiped elastic body section to said ground contacting surface.6. A crawler plate in accordance with claim 1 wherein said transversewidth of the crawler plate is smaller than a link pitch when links aremounted on said link mounting surface.
 7. A crawler plate in accordancewith claim 1 wherein said ground contacting surface side includes aground contacting surface which extends substantially parallel to saidlink mounting surface and to said longitudinal length of said crawlerplate.
 8. A crawler plate in accordance with claim 7 wherein a width ofsaid ground contacting surface is smaller than said transverse width ofsaid crawler plate.
 9. A crawler plate in accordance with claim 7wherein each longitudinally extending side of said crawler plateincludes an inversely-warped initial contact surface, extending fromsaid link mounting surface side toward said ground contacting surfaceside, and a subsequent contact surface, connecting an edge, closest tosaid ground contacting surface, of said inversely-warped initial contactsurface with an edge of said ground contacting surface.
 10. A crawlerplate in accordance with claim 9 wherein an angle, which is formed by(a) a line extending from a link pin center of a link, when mounted onsaid crawler plate, to said inversely-warped initial contact surface and(b) a line extending from the link pin center perpendicular to saidground contacting surface, is equal to or less than an angle, which isformed by (a) a line connecting the link pin center and said subsequentcontact surface and (b) a line extending from the link pin centerperpendicular to said ground contacting surface, so that a portion ofsaid inversely-warped initial contact surface would contact a portion ofan inversely-warped initial contact surface of an adjacent similarelastic-bodied crawler plate in a crawler band at the beginning ofinverse warping of the crawler band, and so that as the inversely-warpedangle increases, the contacting portions extend so that said subsequentcontact surface contacts a subsequent contact surface of said adjacentsimilar elastic-bodied crawler plate.
 11. A crawler plate in accordancewith claim 9, wherein said elastic body comprises a rectangularparallelepiped elastic body section, forming said link mounting surfaceside of said crawler plate and including the inversely-warped initialcontact surfaces, and a trapezoidal elastic body section, forming saidground contacting surface side of said crawler plate and including thesubsequent contact surfaces.
 12. A crawler plate in accordance withclaim 11, wherein a width of said ground contacting surface graduallydecreases from a central area of said crawler plate toward eachlongitudinal end of said crawler plate, without changing the width ofsaid link mounting surface side of said crawler plate.
 13. A crawlerplate in accordance with claim 12, wherein said trapezoidal elastic bodysection has longitudinally extending sides and opposite ends, whereineach longitudinally extending side of said trapezoidal elastic bodysection comprises first and second slanting surfaces with each extendingfrom said central area of said crawler plate to a respective end of saidtrapezoidal elastic body section.
 14. A crawler plate in accordance withclaim 13, wherein each end of said trapezoidal elastic body section isin the form of a trapezoidal end surface slanting in an inward directionfrom said rectangular parallelepiped elastic body section to said groundcontacting surface.
 15. An elastic-bodied crawler plate having alongitudinal length, a transverse width, a link mounting surface side, aground contacting surface side, opposite longitudinally extending sides,and opposite longitudinal ends, said crawler plate comprising:an elasticbody including holes for inserting bolts therethrough; a core bodyincluding a link mounting surface; said core body having a plurality ofbolt attaching holes formed therein so as to extend through said linkmounting surface; said crawler plate being integrally formed by saidcore body being embedded in said elastic body with said core body havingexposed surfaces which are not covered by said elastic body and withsaid link mounting surface side including said link mounting surface;said exposed surfaces including bolt head bearing surfaces and said linkmounting surface; wherein said ground contacting surface side includes aground contacting surface which extends substantially parallel to saidlink mounting surface and to said longitudinal length of said crawlerplate; wherein said transverse width of the crawler plate is smallerthan a link pitch when links are mounted on said link mounting surface;wherein a width of said ground contacting surface is smaller than saidtransverse width of said crawler plate; wherein each longitudinallyextending side of said crawler plate includes an inversely-warpedinitial contact surface, extending from said link mounting surface sidetoward said ground contacting surface side, and a subsequent contactsurface, which connects an edge, closest to said ground contactingsurface, of said inversely-warped initial contact surface with an edgeof said ground contacting surface; wherein an angle, which is formed by(a) a line extending from a link pin center of a link, when mounted onsaid crawler plate, to said inversely-warped initial contact surface and(b) a line extending from the link pin center perpendicular to saidground contacting surface, is equal to or less than an angle, which isformed by (a) a line connecting the link pin center and said subsequentcontact surface and (b) a line extending from the link pin centerperpendicular to said ground contacting surface, so that a portion ofsaid inversely-warped initial contact surface would contact a portion ofan inversely-warped initial contact surface of an adjacent similarelastic-bodied crawler plate in a crawler band at the beginning ofinverse warping of the crawler band, and so that as the inversely-warpedangle increases, the contacting portions extend so that said subsequentcontact surface contacts a subsequent contact surface of said adjacentsimilar elastic-bodied crawler plate.
 16. An endless crawler bandcomprising:a plurality of crawler plates positioned adjacent one anotherin an endless loop, each of said crawler plates being clamped to arespective pair of links by bolts, the pair of links on each crawlerplate being connected to the pairs of links on adjacent crawler platesby pins; each of said crawler plates having a longitudinal length, atransverse width, a link mounting surface side, a ground contactingsurface side, opposite longitudinally extending sides, and oppositelongitudinal ends, each said crawler plate comprising:an elastic bodyincluding holes for inserting bolts therethrough; a core body having asmooth top surface, without an abrupt convex or concave form, and asmooth bottom surface, without an abrupt convex or concave form; saidsmooth top surface including a link mounting surface; said core bodyhaving a plurality of bolt attaching holes formed therein so as toextend through said link mounting surface; said crawler plate beingintegrally formed by said core body being embedded in said elastic bodywith said core body having exposed surfaces which are not covered bysaid elastic body and with said link mounting surface side includingsaid link mounting surface; said exposed surfaces including bolt headbearing surfaces and said link mounting surface.
 17. An endless crawlerband in accordance with claim 16, wherein each said elastic bodycomprises a rectangular parallelepiped elastic body section forming anelastic body portion of the link mounting surface side of the crawlerplate and a trapezoidal elastic body section forming an elastic bodyportion of the ground contacting surface side of the crawler plate. 18.An endless crawler band in accordance with claim 17, wherein a width ofsaid ground contacting surface gradually decreases from a central areaof the crawler plate toward each longitudinal end of the crawler plate,without changing the width of said link mounting surface side of thecrawler plate.
 19. An endless crawler band in accordance with claim 18,wherein each said trapezoidal elastic body section has longitudinallyextending sides and opposite ends, wherein each longitudinally extendingside of the trapezoidal elastic body section comprises first and secondslanting surfaces with each extending from said central area of thecrawler plate to a respective end of the trapezoidal elastic bodysection.
 20. An endless crawler band in accordance with claim 19,wherein each end of the trapezoidal elastic body section is in the formof a trapezoidal end surface slanting in an inward direction from therectangular parallelepiped elastic body section to the ground contactingsurface.
 21. An endless crawler band in accordance with claim 16 whereinthe ground contacting surface side includes a ground contacting surfacewhich extends substantially parallel to the link mounting surface and tothe longitudinal length of the crawler plate.
 22. An endless crawlerband in accordance with claim 21 wherein the transverse width of thecrawler plate is smaller than a link pitch when links are mounted on thelink mounting surface.
 23. An endless crawler band in accordance withclaim 21 wherein a width of the ground contacting surface is smallerthan the transverse width of the crawler plate.
 24. An endless crawlerband in accordance with claim 23 wherein each longitudinally extendingside of the crawler plate includes an inversely-warped initial contactsurface, extending from the link mounting surface side toward the groundcontacting surface side, and a subsequent contact surface, connecting anedge, closest to the ground contacting surface, of the inversely-warpedinitial contact surface with an edge of the ground contacting surface.25. An endless crawler band in accordance with claim 24 wherein anangle, which is formed by (a) a line extending from a link pin center ofa link, mounted on the crawler plate, to the inversely-warped initialcontact surface and (b) a line extending from the link pin centerperpendicular to the ground contacting surface, is equal to or less thanan angle, which is formed by (a) a line connecting the link pin centerand the subsequent contact surface and (b) a line extending from thelink pin center perpendicular to the ground contacting surface, so thata portion of the inversely-warped initial contact surface of one crawlerplate contacts a portion of an inversely-warped initial contact surfaceof an adjacent crawler plate in the crawler band at the beginning ofinverse warping of the crawler band, and so that as the inversely-warpedangle increases, the contacting portions extend so that the subsequentcontact surface contacts a subsequent contact surface of the adjacentcrawler plate.
 26. An endless crawler band in accordance with claim 24,wherein each elastic body comprises a rectangular parallelepiped elasticbody section, forming the link mounting surface side of the crawlerplate and including the inversely-warped initial contact surfaces, and atrapezoidal elastic body section, forming the ground contacting surfaceside of the crawler plate and including the subsequent contact surfaces.27. An endless crawler band in accordance with claim 26, wherein a widthof the ground contacting surface gradually decreases from a central areaof the crawler plate toward each longitudinal end of the crawler plate,without changing the width of the link mounting surface side of thecrawler plate.
 28. An endless crawler band in accordance with claim 27,wherein the trapezoidal elastic body section has longitudinallyextending sides and opposite ends, wherein each longitudinally extendingside of the trapezoidal elastic body section comprises first and secondslanting surfaces with each extending from the central area of thecrawler plate to a respective end of the trapezoidal elastic bodysection.
 29. An endless crawler band in accordance with claim 28,wherein each end of the trapezoidal elastic body section is in the formof a trapezoidal end surface slanting in an inward direction from therectangular parallelepiped elastic body section to the ground contactingsurface.
 30. An endless crawler band in accordance with claim 26,wherein the inversely-warped initial contact surfaces of an adjacentpair of crawler plates have initial contact portions moving on loci ofintersecting circular arcs having their centers at centers of link pinswhich connect the links of the adjacent pair of crawler plates to othercrawler plates, and the initial contact portions are boundary portionsbetween opposing inversely-warped initial contact surfaces and opposingsubsequent contact surfaces of said adjacent pair of crawler plates. 31.An endless crawler band in accordance with claim 30, wherein onattaching the pair of crawler plates, having opposing initial contactportions to their links, the attachment is conducted so that the loci ofthe movement of the opposing initial contact portions move on the lociof intersecting circular arcs, having their centers at centers of linkpins which connect the links of the adjacent pair of crawler plates toother crawler plates and having radiuses, so that the pair of crawlerplates are clamped to their links with a space between the opposinginitial contact portions so that a position of intersection of theopposing initial contact portions contacting and intersecting each otheris within the range from the initial contact portions to upper endportions of the link mounting surface sides of the pair of crawlerplates.